Expansion Tectonic modelling studies outlined here utilise modern geological mapping published by the Commission for the Geological Map of the World and UNESCO (1990) to constrain plate assemblages on small Earth models. This mapping was not available to early researchers into continental drift, plate tectonics, or Earth expansion.

It is important to note that this map was originally commissioned and completed in order to quantify the plate motion histories and plate assemblages on a constant radius plate tectonic Earth. However, this map is rarely used in plate tectonic studies today simply because it failed to achieve this intended aim.

The Expansion Tectonic modelling studies presented here demonstrate conclusively that assemblage of each of the crustal plates on small Earth models coincide fully with the seafloor spreading and geological evidence and accord precisely with the ancient Earth radii derived from measured surface areas. This coincidence applies not only to the more traditional oceans, such as the Atlantic Ocean where conventional reconstructions agree in principle, but also to the Pacific Ocean where the necessity for subduction of all or part of the seafloor crusts generated at spreading ridges is refuted.

It is emphasised that this published Geological Map of the World is factual evidence and the Expansion Tectonic modelling and research undertaken can therefore be justly considered as empirical research. The most fundamental question considered during this research was:

Does the seafloor mapping really reflect an increase in Earth radius with time?

This question was dually answered and tested by measuring each of the seafloor surface areas in turn and from this, calculating ancient Earth radii for each interval of time back to the Triassic Period. These results were then further quantified by using the radii data to create small Earth models. These models were in turn used to test whether or not the remaining seafloor and continental crustal plate data will reassemble back in time to ultimately assemble as Pangaea and primordial Archaean supercontinental small Earth models respectively.

By progressively removing each coloured seafloor stripe in turn it is shown that the plate fit-together along each mid-ocean-ridge plate margin achieves a better than 99% global fit for all models constructed. This modelling study empirically demonstrates that, once seafloor crusts have been removed, all remaining continental crusts do indeed assemble as a complete Pangaean Earth at approximately 50 percent of the present Earth radius during the late-Permian–some 250 million years ago.

This unique fit-together empirically demonstrates that a post-Triassic Expansion Tectonic Earth is indeed a viable process and therefore justified extending modelling studies back further to the early-Archaean times.

Quantification of an Expansion Tectonic Earth process back to the early-Archaeantimes required an extension of the fundamental cumulative seafloor volcanic crust premise to include continental crusts. Continental crust was modelled on pre-Triassic small Earth models by considering the primary continental crustal domains called cratons, orogens, and basins. In order to achieve this modelling, consideration was given to an increase in surface area during an increase in Earth radius occurring as a result of crustal stretching and extension within an established network of continental sedimentary basins.

Moving back in time, any crustal extension must then be progressively restored to a pre-extension, pre-stretching, or pre-rift crustal configuration by simply removing young sedimentary and intruded magmatic rocks and reducing the surface areas of each of the sedimentary basins in turn, consistent with the empirical data shown on the Geological Map of the World.

During this crustal restoration process, the spatial integrity of all existing ancient cratons and orogens was retained until further restoration to a pre-orogenic configuration was required. By removing all basin sediments and magmatic rocks, as well as reducing the surface area of each sedimentary basin in turn, an ancient primordial small Earth with a radius of approximately 27 percent of the present Earth radius was then achieved during the early-Archaean–some 4,000 million years ago.

This primordial Earth comprises an assemblage of the most ancient Archaean cratons and Proterozoic orogenic rocks: all other rocks were simply returned to their places of origin.

Mathematical modelling of both the seafloor and continental crustal surface area data demonstrates that the Earth is undergoing an exponential increase in surface area and radius, commencing from a primordial Earth of approximately 1,700 kilometres radius during early-Archaean times. From this, a current rate of increase in Earth radius is calculated to be 22 millimetres per year.

The calculated rate of increase in Earth radius throughout the Archaean to mid-Proterozoic times was of the order of microns per year. Earth radius then steadily to rapidly increased during the late-Proterozoic times–some 1,000 million years ago–and has continued increasing to the present-day. Extrapolating this increase to the future demonstrates that expansion to 5 million years in the future is consistent with a continued spreading along all present-day mid-ocean-ridge axes.

The evolution of the supercontinents during pre-Triassic times simply involved a progressive and evolutionary crustal process during a prolonged period of crustal stretching, accompanied by changes in both Earth surface area and surface curvature through time. The outlines and configurations of the identified supercontinents were then dictated by changes to the ancient sea-levels and distribution of coastal shorelines, primarily as a result of changes to the surface areas of each of the ancient seas.

From this small Earth modelling exercise it was shown that, prior to the Triassic Period, the ancient supercontinents existed as a complete supercontinental crustal shell for approximately 94 percent of early Earth history, lasting for some 3,750 million years. This supercontinental crust covered the entire Earth with no large intervening oceans.

Crustal assemblages on each of the small Earth models also shows that large conventional Panthalassa, Tethys, and Iapetus Oceans are not required during reconstruction. These oceans are instead replaced by continental Panthalassa, Iapetus, and Tethys Seas, which represent precursors to the modern Pacific and Atlantic Oceans as well as ancient sedimentary basins located on many of the present-day continents. Similarly, emergent land surfaces during the Precambrian and following Palaeozoic Eras are shown to equate to the conventional Rodinia, Gondwana, and Pangaea supercontinents and smaller sub-continents.

Fundamental to the concept of Expansion Tectonics is the premise that the volume of ocean waters and atmospheric gases has been accumulating throughout time in sympathy with the formation of ancient supercontinental crusts and extrusion of new seafloor volcanic lava along the mid-ocean-rift zones.